For example, Patent Literature 1 discloses an internal combustion engine which includes a turbosupercharger. This internal combustion engine includes an exhaust gas recirculation passage (EGR passage) for introducing recirculated exhaust gas (EGR gas) into an intake passage on a downstream side of a compressor of the turbosupercharger, and an exhaust gas recirculation valve (EGR valve) for opening and closing the EGR passage. The aforementioned internal combustion engine further includes an air bypass passage that connects a portion of the intake passage on the downstream side of the compressor and a portion of the intake passage on an upstream side of the compressor, and an air bypass valve that is configured to open when the operation of the engine transitions from a supercharging operation state to a deceleration operation state to thereby open the air bypass passage. The air bypass passage is connected to a portion of the intake passage on an upstream side of a connection portion of the EGR passage.
In an internal combustion engine which includes an EGR passage and an air bypass passage having the similar configuration to the ones of the internal combustion engine described in Patent Literature 1, if the air bypass valve is opened when a predetermined condition for opening the air bypass valve is met in a situation in which EGR gas is being introduced into the intake passage through the EGR passage, the air that includes EGR gas will be recirculated via the air bypass passage into the intake passage on the upstream side of the compressor. If the EGR valve is open continuously after the air bypass valve is opened in such a situation, the introduction of EGR gas into the intake passage will be continued. As a result, the gas that is taken into the compressor again corresponds to a gas that is obtained by, after the recirculation of the air, adding an EGR gas with respect to the air that has already been mixed with an EGR gas. Therefore, in the aforementioned situation, if the EGR valve cannot be closed with a high responsivity concurrently with the opening of the air bypass valve, intake air that includes a higher concentration of EGR gas than initially envisioned may be introduced into a cylinder. Consequently, there is a concern that torque fluctuation or misfire may occur.
Including the above described literature, the applicant is aware of the following literature as literature related to the present invention.